If Amex is to introduce a higher tier Aero card, the fee will be in the $599-$699 range. Possibly more if it were to include status. The highest status I think they would give would be Elite 50K/*A Gold, but it would be a variant of E50K, toned down.
I imagine there will be changes to the Aeroplat as well. Maybe even the Gold to keep customers from ditching the card for a new TD/CIBC card in Jan.
Anyone who was lucky enough to get the Plat/ AeroPlat for one fee is smiling now, especially since Amex won't allow new applicants to have this promo.